The magnitude of electric force exerted by a proton on an electron in a hydrogen atom is. (Given distance of separation between charges, 1 Å)

2.3 × 10^-8 N

$ F = \frac{1}{4\pi \epsilon_0}{e^2}{r^2} = 9\times 10^9 \times \frac{(1.6\times 10^{-19})^2}{(10^{-10})^2} = 9\times 10^9\times 2.56\times 10^{-38}\times 10^{20} = 2.30\times 10^{-8}N$